The present invention relates generally to agricultural machinery such as mobile harvesting machines and, more particularly, to improvements to a measuring device for determining a parameter specific to a harvested crop material.
It is contemplated that the measuring device is on a mobile harvesting machine with an attachment for picking up the crop material and at least one implement for working the crop material. In one example the invention relates to a measuring device for determining a specific parameter, such as moisture and/or conveying, on a forage harvester for the harvesting of silage corn, wilted grass silage or whole crop silage.
German patent 32 32 746 C2 describes a mobile harvesting machine with a device for moisture measurement in the path of the crop material. The moisture measurement is significant in that the moisture content of the crop material in the silage has a critical influence on the subsequent silage quality. With excessively moist crop material or silage butyric acid bacteria may form, which impair the silage quality. These adverse resulting phenomena of excessively moist crop material can however be compensated to a large extent by the addition or admixture of additives on recovery of the crop material. The quantity of additives needed depends on the moisture of the crop material, which can be completely different even within one cutting. To be able to correctly dose addition of the additives, online moisture measurement by means of a corresponding measuring device directly on the path of the crop material through the harvesting machine, as described in German patent 32 32 746 C2, is necessary.
In practice the location of mounting and the position of fitting the measuring device within the path of the crop material is problematic, both with respect to a reliable measuring result and with respect to wear and soiling of the measuring device. Experiments with a measuring device, specifically a moisture sensor which measures the electrical conductivity of the crop material, fitted in the adjustable ejector flap of a forage harvester have shown that the measuring results varied for crop materials having the same moisture content depending on the angle of adjustment of the ejector flap. The apparent reason for this is that the angle between the stream of crop material and the measuring device and the associated contact pressure of the crop material on the moisture sensor differ depending on the angle of adjustment of the ejector flap. With this sensor the contact pressure, as a disturbance variable, has a great influence on the measured moisture value. However, to allow optimum filling of a truck or trailer moving parallel to the forage harvester, very frequent adjustment of the ejector flap is necessary. As a result, unreliable moisture measurement with high fluctuations of measured value is unavoidable.
In addition, a measuring device located in the ejector flap is subject to high abrasive wear by the impinging crop material which is greatly accelerated up to 70 m/s (about 230 ft./sec.) by an ejector blower. Thus, the durability of the measuring device is considerably reduced. The abrasive wear is further increased by the fact that under certain circumstances earth, small pieces of wood or stones cling to the crop material, which however cannot be prevented.
Very high wear and damage may occur even if the measuring device is located in front of the working unit, i.e. the blade drum or the chopper assembly, of the forage harvester. If this site is chosen, the precision of measurement is for example lower in case of moisture measurement, as only the surface moisture of the raw material and not the actual moisture of the chopped material is measured.
Other sites, for example in the ejector pipe bend, which of course exhibit lower abrasive wear, show the problem of soiling and poor accessibility of the measuring device. The fibrous crop material forms deposits, particularly in case of a high moisture content, when sufficient self-cleaning by the stream of crop material does not occur at the measuring point. This can lead to false or unusable measuring results.
In German patent 32 32 746 C2 these problems are not addressed. Only some basically possible locations for fitting a moisture measuring device on a combine harvester are proposed. Indications of suitable mounting locations and positions of the measuring device for solving the above-mentioned problems are not found therein.
It is therefore an object of the present invention to overcome one or more of the above-described deficiencies.
Another object is to mount a measuring device, known in the art for determining parameters specific to crop material and/or conveying on a mobile harvesting machine, in such a way that it delivers reliable measuring results and is moreover protected from wear and soiling.